//------------------------------------------------------------------------------------
// Copyright 2015 Google Inc. All Rights Reserved. 
//
// Distributed under MIT license.
// See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
//------------------------------------------------------------------------------------

namespace SharpVectors.Compressions.Brotli
{
    /// <summary>Lookup tables to map prefix codes to value ranges.</summary>
    /// <remarks>
    /// Lookup tables to map prefix codes to value ranges.
    /// <para> This is used during decoding of the block lengths, literal insertion lengths and copy lengths.</para>
    /// <para> Range represents values: [offset, offset + 2 ^ n_bits)</para>
    /// </remarks>
    internal static class Prefix
	{
        public static readonly int[] BlockLengthOffset = new int[] 
        {
            1, 5, 9, 13, 17, 25, 33, 41, 49, 65, 81, 97, 113, 145, 177,
            209, 241, 305, 369, 497, 753, 1265, 2289, 4337, 8433, 16625
        };

        public static readonly int[] BlockLengthNBits = new int[] 
        {
            2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8, 9, 10, 11, 12, 13, 24
        };

        public static readonly int[] InsertLengthOffset = new int[] 
        {
            0, 1, 2, 3, 4, 5, 6, 8, 10, 14, 18, 26, 34, 50, 66, 98, 130, 194, 322, 578, 1090, 2114, 6210, 22594
        };

        public static readonly int[] InsertLengthNBits = new int[] 
        {
            0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 12, 14, 24
        };

        public static readonly int[] CopyLengthOffset = new int[] 
        {
            2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 18, 22, 30, 38, 54, 70, 102, 134, 198, 326, 582, 1094, 2118
        };

        public static readonly int[] CopyLengthNBits = new int[] 
        {
            0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 24
        };

        public static readonly int[] InsertRangeLut = new int[] 
        {
            0, 0, 8, 8, 0, 16, 8, 16, 16
        };

        public static readonly int[] CopyRangeLut = new int[] 
        {
            0, 8, 0, 8, 16, 0, 16, 8, 16
        };
	}
}
